1y2a
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Structure of mammalian importin bound to the non-classical PLSCR1-NLS
OverviewOverview
Nuclear import of proteins containing a classical nuclear localization, signal (NLS) is an energy-dependent process that requires the heterodimer, importin alpha/beta. Three to six basic contiguous arginine/lysine, residues characterize a classical NLS and are thought to form a basic, patch on the surface of the import cargo. In this study, we have, characterized the NLS of phospholipid scramblase 1 (PLSCR1), a, lipid-binding protein that enters the nucleus via the nonclassical NLS, (257)GKISKHWTGI(266). This import sequence lacks a contiguous stretch of, positively charged residues, and it is enriched in hydrophobic residues., We have determined the 2.2 A crystal structure of a complex between the, PLSCR1 NLS and the armadillo repeat core of vertebrate importin alpha. Our, crystallographic analysis reveals that PLSCR1 NLS binds to armadillo, repeats 1-4 of importin alpha, but its interaction partially overlaps the, classical NLS binding site. Two PLSCR1 lysines occupy the canonical, positions indicated as P2 and P5. Moreover, we present in vivo evidence, that the critical lysine at position P2, which is essential in other known, NLS sequences, is dispensable in PLSCR1 NLS. Taken together, these data, provide insight into a novel nuclear localization signal that presents a, distinct motif for binding to importin alpha.
About this StructureAbout this Structure
1Y2A is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.
ReferenceReference
Phospholipid scramblase 1 contains a nonclassical nuclear localization signal with unique binding site in importin alpha., Chen MH, Ben-Efraim I, Mitrousis G, Walker-Kopp N, Sims PJ, Cingolani G, J Biol Chem. 2005 Mar 18;280(11):10599-606. Epub 2004 Dec 17. PMID:15611084
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